Method of making battery connections



Jan. 30, 1951 E. F. sTElNHoFF` METHOD oF MAKING BATTERY CONNECTIONS Filed Jan. 30, 1947 SPRAYED COPPER O. g j m 21 fOr/1 INVENT wwf gQ/gwo/ogjm @oe @M @K1/@0- Patented Jan. 30, 1951 METHOD oF MAKING BATTERY coNNEcTroNs Ernest F. Steinhofl, Freeport, Ill., asslgnor, by

mesne assignments, to Burgess Battery Company, Freeport, Ill., a corporation of Delaware Application January 30, 1947, Serial No. 725,197

1 This invention relates to multiple cell batteries and the method of making the same. In particular, it relates to an improved method of connecting the cells together in which a metal spraying operation is used instead of the usual soldering operation.

In thermaking of multiple cell batteries, it has been common practice to form the intercell connections by a soldering operation in which the positive terminal of one cell is soldered to the negative terminal of the adjacent cell, or a separate connecting wire is arranged between such terminals and soldered to them to form the intercell connector.

,connections has advantages, the chief of which are that the connections can be made more rapidly, the cost of some of the battery parts isles, and the testing of the cells is facilitated. The connections made by the spraying process have been found to be satisfactorily conductive and capable of withstanding all of the handling and use to which the batteries are normally put.

Accordingly, it is the object cf the invention to provide an improved method of forming the intercell connections by a metal spraying operation.

In the drawing:

Fig. 1 is an elevational view, partly in section, of the battery of the invention, employing the sprayed metal connections;

Fig. 2 is a plan view of one of the cells ofthe battery with the top sealing composition removed;

Fig. 3 is a sectional elevational view of a fragment of the battery at an intermediate stage in the process of forming the connection; and

Fig. 4 is a fragmentall view illustrating the method of severing the carbon electrodes.

While the metal spraying process for forming 4 Claims. (Cl. 13G-175) rubber hydrochloride, or the like. Within the envelope I2 is a negative electrode I3 composed of a suitable metal, such as zinc. Said electrode is in the general shape of a tray, having a fiat main section I4 adjacent to one of the broad surfaces of the envelope I2, and two side flanges kIliand a bottom i ilange I6 extending s substantially per-i' of active depolarizing material 20, which may be composed of a mixture of powdered manganese dioxide and carbon. Both the active body 20 and the separatingr member I8 are moistened with ihe electrolyte, which may be an aqueous solution of ammonium chloride and zinc chloride. Embedded within the active body 20 and projecting i upwardly therefrom is a slender rod-shaped posithe intercell connections may be employed with the copolymer of, vinyl chloride and vinylacetate,

tive electrode 2| which may be composed-of a suitable material, such as carbon. The electrode 2| forms the other conductive terminal for the cell. The elements are enclosed at the bottom and the sides by the non-conductive envelope I2, and the positive electrode 2| and the tab I'I project upwardly above the open top of the envelope.

All of the cells are of similar construction and they are arranged in the casing I0 in juxtaposed relationship and in pressure engagement with each other, whereby the elements of the individual cells are in pressure contact with each other.

A plate of conductive metal 23, which may be zinc, is inserted inthe casing I0 at one end thereof, said plate 23 being of a size and shape similar to that of the main sections I4 of the metal electrodes I3, and having an elongated tab 24 similar to the tabs I'I extending upwardly therefrom. AnA elongated conductor 25 is connected at" positive electrode 2| of the adjacent cell and the end portion thereof is bent so as to partially overlie the top end of said positive electrode. The tabs I1 are connected to the positive electrodes 2| by masses of sprayed metal 28, as will be described more fully hereinafter, whereby the cells are connected together in series. The tab 24 of the metal plate 23 is similarly arranged and connected t9 the positive electrode 2| of the cell adjacent to said plate. A mass of fusible sealing composition 21 illls the open top portions of the envelopes I2 and the casing III, and forms a seal closure for the cells and the battery.

I In the construction of the battery, the cell elements are ilrst assembled into the cell units Il, on'e of which is shown in Fig. 2. At this stage, the positive electrodes, 2|' are longer and extend upwardly to a higher level than they do in the completed battery, as is shown in Fig. 3. The cells and the plate 22 are then placed in the casing I0, and the tab 24 of the plate 23 and the tabs |1 of the metal electrodes I2 are bent so as to extend in a generally horizontal direction into substantially contiguous relation to the positive electrodes 2| of. the adjacent cells at a level below the top edge of the casing I0. The tabs 24 and I1 are then turned so that they extend upwardly in subsfantial contact with the positive electrodes 2| to a level somewhat above the top edge of the casing III, as shown in Fig. 3. The positive electrodes 2| extend upwardly farther than do the tabs 24 and I1. The sealing composition 21 is then poured in place in the molten condition and allowed to cool and solidify. In the arrangement shown, the upper surface of the sealing composition 21 is at substantially the same level as the v top edge of the inner casing I0. The positive electrodes 2| are then severed at substantially the top level of tl. e sealing composition 21. This may be accomplished by any suitable method. A pair of snippers 28, as shown in Fig. 4, has been found to be suitable. The laws 29 thereof are placed on opposite sides of the electrode 2| at the surface level of the sealing composition 21 and upon manipulation of the handles 2U, either manually or by machine, the electrode 2| is severed accurately at the desired point. The severing of the electrodes 2| provides them with fresh clean end surfaces for attachment to the tabs |1.

The tabs |1 and 24 are constructed so that their width is less than the diameter of the carbon electrodes 2| and the Jaws 29 of the snippers are closed only sumciently to cut into the electrodes but not the tabs. The electrodes are brittle and are severed satisfactorily by such operation. For example, with tabs having a width of .035 inch and electrodes having a diameter of .060 inch, the severance takes place satisfactorily. With machine operation. it has been found that a row of electrodes can be severed very rapidly. If it is desired to elect the broken off end portions of the electrodes 2|, this may be done in any suitable manner, as by an air blast.

The upwardly projecting portions of the tabs I1 and 24 are thenbent down horizontally so as to overlie and be substantially in contact with the top end l surfaces of the positive electrodes 2|. This may be accomplished by drawing a blunt instrument along the top of the battery. It is desirable that the exposed surfaces of the tabs be clean so that the sprayed metalwill adhere readily to them, and, in practice, an instrument having 4 and the cleaning of the tab ends. The bent down end portions of the tabs 24 and I1 preferably have a length less than the diameter of the electrodes 2| and only partially overlie the ends of said electrodes. whereby substantial portions of the end surfaces of the electrodes are exposed.

v'The tabs 24 and I1 are then connected to the electrodes 2| by spraying a molten metal against their exposed surfaces. While any suitable metal may be employed, copper has been found to give satisfactory results and is preferred. Any ordinary apparatus for spraying molten metal may be employed, and the spray is directed at an angle substantially less than to the top surface of the battery. While the angle is not critical, an angle of approximately 45 has been found to give satisfactory results and is preferred. It has been found that if the spray is directed at such an inclined direction, the molten metal does not adhere to the surface of the sealing composition 21 while it does adhere to the exposed surfaces of the tabs I1 and 24 and the electrodes 2|. To avoid heating the sealing composition 21 to the point where it softens and flows under the influence of the spray, the latter is directed at the same spoJ for only a short period of time. and several sprays are given to build up the connecting masses of metal to a suitable thickness. For the best results, the sealing composition should have a hard surface and should not have too low a soit ening point. It has been found that a hard sealing wax composed of approximately three parts by weight of gum rosin and two parts of a illler such as powdered silica is quite satisfactory, having a hard smooth surface and a softening point higher than F.

In practice, the spray is applied continuously and is moved across the top surface oi the battery. It is usually necessary to do this several times toy build up the metal to the desired thickness. The spray is preferably applied from aff' different direction during each movement across the battery. For example, while maintaining the direction of the spray substantially constant. the battery may be sprayed once. then turned horizontally through an angle of 90 and given a second spray, and this operation may be repeated until the battery has been sprayed from four different directions. For the economical operation of the process, a number of the battery units may be arranged together upon a platform or in a Jig, and the platform or Jig may be turned between successive spraying operations until the batteries have been sprayed from four different directions. In this manner, a connecting mass 26 of metal having substantial thickness is built un upon the contiguous exposed portions of the tabs I1 and 24 and the electrodes 2|, which mass adheres firmly to said members and forms conducting bridges upon the exposed surfaces of said members. At the same time, the molten metal does not adhere to the top surface of the sealing composition 21, or to any other surface where its presence is not desired. With a small amount of practice, an operator soon become proficient in the rapid formation of satisfactory connections.

an abrasive surface, such as an emery stone, is

drawn along the top surface of the battery.l This accomplishes `simultaneously both the bending 'I'he process has the primary advantage that it can be carried out very rapidly. In addition. it makes possible economies in construction. For example, in most battery constructions `employing carbon rod electrodes. the carbon rods are provided with conductive metal caps which fit tightly over the top ends thereof. When the sprayed met connections of the present inveni tion are used, such metal caps may be dispensed with. In addition, the solder and soldering operations previously employed are dispensed with,

along with the necessity for selecting an active easily accessible contacts for testing the vcells individually after the battery has been assembled. Also, the process is adapted for rapid machine operation.

After the battery has been formed as described, it may, if desired, be dipped in a body of molten 6- 2. In making a battery of electrically connected cells each having a slender carbon terminal and a flexible. metal terminal projecting from the same side of said battery, the steps which comprise ap.

plying a layer of sealing compound W said side of said battery in such manner as to leave the end portions of said terminals exposed, severing non-conductive com-position such as wax or pitch,

so as to cover the exposed connections 26 and form a thin insulating coating' over the entire battery, including the casing I0. A support for the battery terminals, composed of a number of layers of non-conductive material as shown, y

may be arranged at one end of the battery, and one terminal 36 carried thereby may be connected to the conductor 25 and the other terminal 31 carried thereby may be connectedto the conductor 22. Saidconnections may be made by means of solder or other suitable means. The whole is then enclosed in an outer carton 38 of suitable non-conductive composition, such as paperboard', which has an opening 39 at an end thereof to provide access tothe terminal member 35.

While but a singlemodification of the invention has been described and illustrated, this is by way of example and various modications may be made within the scope of the invention as the same is set forth in the appended claims. For example, instead of spraying against the entire top surface of the battery, a stencil sheet of metal or other suitable composition may be placed overfthe top of the battery, such sheet having openings registering with the positive rected through the openings to form' the conn ecting masses 26. In such case, the ,spray may be directed vertically downward upon the battery.

Also, instead of employing the tabs I1 which- 2i by a spraying operation asv described. Such` the exposed portions of said .carbon terminals to provide clean ends for said carbon terminals, bending the ilexible terminal of one cell into contiguous and partially overlying relationship to the end of the slender carbon terminal of a different cell, and spraying molten metal upon said contiguous portions of said terminals whereby said sprayed metal upon solidifying forms conductive connections between said contiguous terminals.

3. In making a battery of electrically connected cells each having a slender carbon terminal and a flexible metal terminal projecting from the same side of said battery, the steps which comprise applying a layer of sealing compound to said lside of said battery in such manner as to leave the end portions of said terminals exposed, bending the ilexible terminal of one cell into contiguous and partially overlying relationship to the end of the slender carbon terminal of a dif--` ferent cell, and spraying molten metal upon said contiguous portions of said terminals while directing said spray at an angle substantially less than 90 degrees tothe exposed surface of said sealing layer, whereby said sprayed metal upon solidifying forms conductive connections between cells each having a slender carbon terminal and a. iexible metal terminal projecting from the same side of said battery, the steps which comprise applying a layer of sealing compound to said velectrodes 2i. The metal spray may then bediside of said battery in such manner as to leave the endv portions of said terminals exposed, bending the ilexible terminal of one'cell into contiguous and partially overlying relationship to the -end of the slender carbon terminal of a diilerent cell, and sprayingmolten copper upon said contiguous portions of said terminals while directing said spray at an angle substantially less than 90 degrees to the exposed surface of said sealing layer, whereby said sprayed metal upon solidifylng forms conductive connections between said separate wire type of connections may be used to advantage where the ordinary cylindrical type of dry cell having a cup-shaped metal electrode;

is used.

What is claimed is:

1. In making a batteryof electrically connected cells each having a slender carbon terminal and a flexible metal terminal projecting from the same` REFERENCES CITED The following. references are of record in the 1116.01 this patent:

UNITED STATES PATENTS Number Name Date 1,639,280 Benner et al. Aug. 16, 1927 1,670,040 McCabe May 15, 1928 1,723,727 Eckstein Aug. 6, 1929 1,758,362 Gillingham May 13, 1930 1,984,925 Gahn Dec. 18, 1934 `2,361,378 Brennan Oct. 31, 1944 FOREIGN PATENTS Number Country Date 255,967 Great Britain Aug. 5, 1926 313,154 Germany June 27, 1919 OTHER 'REFERENCES Cook, V. A.:` Mogul Metallizer, Sept-Oct. 1944, P880 6. 

